How to print UART message in "ble_app_uart" project in SDK15.2

[chianglin]

Hi,

Does "ble_app_uart" project can print debug message from "UART" interface? How can I do this job?

PS. My UART Port is at P0.18 (TX) and P0.19(RX).

Thank you,

Chianglin

[Vidar Berg]

Hi,

The ble_app_uart project prints debug messages over Segger RTT by default.  But you can use printf() if you wish to write data to the UART.

Vidar

[chianglin]

Hi Vidar,

I had try to use printf() to write data to UART, and the UART interface is connect to PC, but I can not find any data  in PC console.

My environment is:

1. Use Nordic's nRF52832 EVM board.

2. Use "ble_app_uart" project of SDK15.2, and I doesn't modify any thing.  Actually, there have "printf()" function in main.c.

But I still can not found any message from PC via UART interface.

How can I fix this problem?

Thank you,

Chianglin

[Vidar Berg]

chianglin said:

Can I modify TXD to P0.18 and RXD to P0.19 for UART output?

It shouldn't be a problem, but make sure that the RXD pin isn't left floating as that may cause framing errors, etc due to noise.

[chianglin]

Hi Vidar,

I think P0.18 and P0.19 don't have problem to define as UART, because this 2 pins can work correct when I use "peripheral\uart" project.

The "nRF UART APP" can not find the BLE device which describe In my previous mail. May be the device had been crash, so BLE can not work.

The only change between “BLE can work or not" is "I modify the tx_pin_no and rx_pin_no in structure "comm_params".

Would you please tell me why my device is crash after I do these change?

Thank you,

Chianglin

[chianglin]

Hi Vidar,

It's work now.  It should have something wrong in my previous process step.

Thank you for your serious support.

Best Regards,

Chianglin

[Vidar Berg]

Hi,

Glad to hear that it works now, thanks for the update. 

Best regards,

Vidar

[chianglin]

Hi Vidar,,

As well know, EVM have a "JLINK CDC UART".

I use EVM to test "ble_app_uart" project and I execute following setting:

    app_uart_comm_params_t const comm_params =
    {
        .rx_pin_no    = RX_PIN_NUMBER,
        .tx_pin_no    = TX_PIN_NUMBER\,
        .rts_pin_no   = RTS_PIN_NUMBER,
        .cts_pin_no   = CTS_PIN_NUMBER,
        .flow_control = APP_UART_FLOW_CONTROL_DISABLED,
        .use_parity   = false,
#if defined (UART_PRESENT)
        .baud_rate    = NRF_UART_BAUDRATE_115200
#else
        .baud_rate    = NRF_UARTE_BAUDRATE_115200
#endif
    };

When I use "printf" function to out a debug message via UART interface, both "CDC UART" and "UART which use P0.06 for TXD and P0.08 for RXD" will get the same debug message.

Can I print different debug message to these two UART port?

For example, print "ABC" to CDC UART, and print "123" to the other UART port.

Thank you,

Chianglin

[Vidar Berg]

Hi Chianglin,

There's only one UART instance on the 52832. The Jlink chip acts as a UART<->USB bridge when you use P.0.06 and P.0.08